This invention relates to an extruder and more particularly to a new and improved means for feeding material into and through an extruder to improve its efficiency.
Plastic materials in the form of pellets, granules, and buns and or globs of hot melt plastic materials are generally fed via gravity to the hopper of a pelletizing extruder wherein the hopper is mounted on an opening communicating with the central cylindrical passageway of an extruder where the rotating extruder screw is located. The hopper feeds or directs the plastic material into the extruder where the extruder screw plasticates, works, and melts the material into a homogenous melt for discharge therefrom and subsequent cooling and pelletizing into small cubes. In this process, mixers are often employed to preliminarily mix and plasticate the material for discharge into the hopper of the pelletizing extruder as globs or buns of hot melt to assure a better mixing process. In this latter instance, the globs of hot plastic material are often deflected outwardly away or back into the hopper rather than be accepted by the clearance space between the cylindrical barrel wall and the flights of the rotating screws. Heretofore solutions to this problem included the provision of modifying the structural portion of the extruder barrel adjacent to the hopper to provide a larger chamber on the side within the barrel itself to receive the hot melt or to also include in such feed section of the barrel an auxiliary feed screw to cooperate with the main feed screw to aid in the conveying of the hot melt or plastic material. In these instances, the cost is extremely high and renders such modified extruders to limited special uses. Another solution to this problem is to rotate the extruder screw at a much higher speed to push the hot melt forward. Such higher screw feed puts an unnecessary shear heat into the compound, overheating the compound, which results in a poor quality product. These solutions are very expensive. Applicant in his structure provides a deflector plate between the hopper and the extruder barrel opening that communicates with the central passageway to eliminate the need to structurally change the normal extruder barrel or provide a new extruder barrel while doing so with a minimum of cost. Hot melt as used herein refers to plastic materials or mixtures of plastic materials that are pliable and have properties that are putty like in nature as between the state of being a solid and a liquid. Buns or globs of hot melt are much larger in size than cubes or granules of PVC and are lumpish usually rounded masses of usually larger size as about the size of a human's fist.